The chapter traces the development of the Australian ministerial office since 1972 and describes the policy-making role of policy-active ministerial staff. This occurs in three different arenas, each with a different character and purpose: working with the department, working with other ministers and working with stakeholders. It is argued that investigating the work of political staff and its impact comparatively depends fundamentally on how the subject is constructed. Different ways of constructing the subject are proposed, arising from the distinct patterns found in different political systems. An institutional lens is used to analyse the trajectory of Australian political staff over time and the conditions influencing key developments. It is argued that an institutional lens is useful in analysing the trajectories of political adviser cadres over time in different countries, exploring the conditions under which they emerge in different institutional forms (such as hybrid or separate institutions) and whether they are a result of deliberate design or more evolutionary processes.